changeset_status: add unit tests for calculation of overall status Add unit tests for the calculation of the review status of a changeset/pull request. To allow this, some reorganization of the ChangesetStatusModel is needed.

[tox]
envlist = py{26,27}-{pytest,nose}

[testenv]
setenv =
    PYTHONHASHSEED = 0
deps =
    nose: nose
    pytest: pytest
commands =
    nose: nosetests {posargs}
    pytest: py.test {posargs}